The more they destroy, the longer…
The more the destruction, the longer….
Change recovery to the recovery. (2nd clause)
The more…, the longer the recovery.
Change recovery to they will need to recover. (2nd clause)
The more…, the longer they will need to recover.
recovery – getting back to a former or better condtion
parallel wording – like grammatical structure; noun-noun, verb-verb, clause-clause
like (adj.) – of the same form, appearance, kind, character, amount, etc.
longer (adj) – refers to a comparative amount of time